The overall objectives of the proposed research are to fully characterize the clinical phenotype of this hereditary bone dysplasia and cancer and identify the imaging modlities applicable for the diagnosis and early detection of this bone dysplasia in childhood and malignant fibrous histiocytoma in affected patients. The study also proposes to identify the chromosomal localization and gene responsible for this disorder and then to begin defining the role(s) of the gene product in normal cellular functioning and tumorigenic progression.